Electric circuit breaker



Aug. 3, 1943.

34 O\\ 3 J9 Q 44 43' InQentor: John D. Gaye-r,

is Attovney.

Aug. 1943- J. D. GAYER 2,325,949

ELECTRIC CIRCUIT BREAKER Filed Feb. 9, 1942 2 Sheets-Sheet 2 I Inventor:John D. Gayen His Attorney.

Patented Aug. 3, 1943 2,325,949 ELECTRIC CIRCUIT BREAKER John D. Gayer,Springfield, Pa., assignor to General Electri York Company, acorporation oi New Application February 9,1942, Serial No. 430,024 6Claims. (01. 200-82) My invention relates to electric switches such scircuit breakers and the like and more particularly to a restraininglatch for restraining the movement of the contacts of electric switches.

It has been found that, due to vibration and other causes, therelatively movable contacts of a circuit breaker often tend to separatewhen the circuit breaker is closed or the contacts tend to move towardone another when the circuit breaker is open. To reduce the operatingforce required to operate a circuit breaker, the friction of theoperating mechanism is usually held to a minimum value and,consequently, undesirable relative movement of the contcts may result inthe open or closed position of the breaker with consequent danger toapparatus and perhaps even to human life. In the copending applicationof Carl Thumim et al., Serial No. 317,564, filed February 6, 1940, andassigned to the same assigneee as the present application, there isdisclosed and broadly claimed a restraining means for holding thecontacts of an electric switch in a predetermined position with meansfor releasing said re straining means when it is desired to operate theswitch. Also, in the copending application of Carl Thumim et al., SerialNo. 367,789, filed November 29, 1940, and assigned to the same assigneeas the present application, there is disclosed an electric switch inwhich two restraining latches are provided for holding certain contactsof the switch in the open and in the closed position with means forreleasing these latches at cult breaker in either its closed or its openposition and which includes simple means for releasing the latchingmeans at the desired time.

Accordingly, it is an object of my invention to provide a new andimproved restraining means for the contacts of an electric switch.

It is another object oi my invention to provide a single restrainingmeans for holding the relatively movable contacts of an electric switchin a plurality of predetermined positions with means operative uponmovement of said relatively movinvention, and

able contacts for releasing the restraining means.

Further objects and advantages of my invention will become apparent asthe following description proceeds and the features of novelty whichcharacterize my invention will be pointed out with particularity in theclaims annexed to and forming a part of this specification.

For a better understanding of my invention, reference may be had to theaccompanying drawings in which Fig. 1 is a schematic diagram partly insection of an electric switch embodying my Figs. 2, 3, 4, and 5 areenlarged views of a portion of Fig. 1 indicating operating positions ofthe restraining means embodying my invention.

Although my invention is applicable to any types of switches havingrelatively movable contacts whether single-phase or polyphase, I havechosen for purposes of illustration to show my invention as applied toan air-blast circuit breaker of the fluid-operated type. Accordingly, inFig. 1, I have shown my invention as applied to a polyphase circuitbreaker l0, only the structure Illa associated with one set of contactsof the circult breaker being shown since the other poles of the circuitbreaker are identical. Where I have illustrated any operating mechanismfor the various phases or poles which are identical for-each phase orpole, such parts are hereinafter characterized by the same referencenumeral with the letters a, b, or 0, depending upon the particular phaseor pole of the circuit breaker. Circuit breaker I0 is illustrated as ofthe cross-blast type and the pole Illa is illustrated as comprising astationary contact Ha and a movable contact [2a arranged to be operatedso as to rate, an arc is drawn between arcing tips l6a and l2'a.Immediately after separation of the cation.

Each of the movable contacts of the various poles or phases of circuitbreaker Ill, such as I2a,

which alone is illustrated, is connected to corresponding individualoperating rods, such as Illa.

These operating rods, only |9a of which is illustrated, are'connected toone end of suitable levers 20, which levers have the other ends thereofprovided with crossheads 2| arranged to slide in guides 22. Only themechanism including members 20a, 2Ia, and 22a of pole "la isillustrated, however. Each of the levers 20 has an intermediate pointthereon pivotally connected to bell cranks 23a, 23b, and 230,respectively, which, in turn, are pivotally mounted on fixed supports24a, 24b, and 240. This arrangement of cranks 23 and levers I provides astraight-line motion of the contacts I2 in arc chutes I3. In order thatthe movable contacts I2 associated with all the poles of circuit breakerI0 are simultaneously actuated, bell cranks 23a, 23b, and 230, areinterconnected by a horizontally reciprocating operating rod 25. Asillustrated, each of the bell cranks 23 is provided with suitablebufiers, only 26a of which is illustrated, to cushion the closing andopening movements of the operating mechanism and movable parts ofcircuit breaker I0.

Any suitable means may be provided forproducing relative movementbetween the contacts II and I2 of circuit breaker III. In Fig. 1, thismeans is illustrated as a fluid motor, generally indicated at 21',including a'cylinder 28 and a piston 29 operatively connected through aconnecting rod 30, links 3| and 32, and a crank 33, with the bell cranks23a, 23b, and 230 for operating the contacts of circuit breaker III.

In order to operate fluid motor 27 as well as to supply a blast of fluidthrough conduits II, only IIa of which is shown, for arc-extinguishingpurposes, a source of fluid under pressure 34 is provided, which maypreferably be air under pressure. This source of air under pressure 34is connected through a suitable blast valve 35 to conduit Ila as well asto the corresponding conduits for the other poles of circuit breaker IIIand, to this end, a manifold (not shown) may be provided between theseconduits I1 and blast valve 35. Blast valve 35 is preferably constructedas disclosed in copendlng application Serial No. 343,002, filed July 28,1940, on behalf of Carl Thumim, now Patent 2,315,991 and assigned to thesame assignee as the present application. Any suitable means may beprovided for operating blast valve 35 although, in Fig. 1, I haveillustrated this operating means as comprising a sliding bar 36operatively connected to piston 29 of fluid motor 21 and having one ormore cams, such as 31, mounted thereon. Movement of piston 29 causes cam31 to engage a cam follower 38 to open blast valve 35 through pivotallymounted lever 39. As illustrated schematically in Fig. l, cam 31 willproduce a blast of the same duration during both the opening and closingmovements of the circuit breaker. However, it may be desirable incertain cases to have no blast of fluid during the closing operation ofthe circuit breaker or to have a blast of shorter duration during suchclosing operation, in which case, an additional cam having,a differentoperating face than cam 31, will be provided with means for renderingcam 31 inefiective to open the blast valve 35 during the closingoperation of the circuit breaker.

Such an arrangement is disclosed and claimed in United States LettersPatent 2,287,578, filed jointly for Carl Thumim and me, and assigned tothe same assignee as the present application.

The source of fluid 34 is also connected with the respective ends ofcylinder 28 through a solenoid-operated circuit-breaker opening valve 40and a solenoid-operated circuit-breaker closing valve 4|. It should beunderstood by those skilled in the art that opening valve 40 and closingvalve 4| are preferably interlocked mechanically as in copendingapplication Serial No.

317,564, referred to above, or interlocked electrically so that theopening valve 40 is given preference to permit opening of the circuitbreaker even though a fault exists at the instant of closing of circuitbreaker III. The restraining means of my inventiornsenerally indicatedat 42, comprises a single pivotally mounted member or latch 43 pivotedat 44 and biased to rotate in a clockwise direction by spring means 45.Asuitable stop 46 is provided to limit the maximum clockwise rotation oflatch 43. Restraint or latching of the contacts I2 of circuit breaker I0and the operating mechanism associated therewith is obtained byengagement of the cam face 43' of latch 43 with the roller 41 attachedto the end of crank 33 associated with link 3|. With the latch 43 in theposition indicated in Figs. 1 and 2, the contacts I2 and the operatingmechanism are held or restrained in the position assumed when circuitbreaker I0 is closed and vibration or the like cannot cause contactseparation. In Fig. 4, on the other hand,

the latch 43 is indicated in the position where face 43' thereof engagesthe roller 41. so as to hold or restrain the operating mechanism and thecontacts l2 of circuit breaker III in the posi ton which these membersassume when the circuit breaker is open and again vibration or the likecannot cause relative movement of the contacts II and I2.

In order to release latch 43 and permit movement of contacts I2 so as toopen the circuit between terminals I4 and I5 when the mechanism isin theposition indicated in Figs. 1 and 2, I provide a lost-motion mechanismbetween link 3| and crank 33 which comprises a slot 48 in link 3| and apin 49 cooperating therewith and mounted in crank 33. Also latch 43 isprovided with a cam face 43" which cooperate with a roller 50 mounted onlink 3 I. Upon initial movement of piston 29 to the left from theposition indicated in Fig. 1, link 3| is moved to the left so thatroller 50 operating on cam surface 43" causes counterclockwise rotationof latch 43 to the position indicated in Fig. 3. Also, by virtue of theslotted connection between link 3| and crank 33, no movement of thecontacts I2 of circuit breaker III has resulted until latch 43 iscompletely released and such movement is permitted. It should also benoted, that, with this slotted connection between link 3| and crank 33,blast valve 35 is opened to insure a blast of fluid adjacent relativelymovable contacts II and I2 prior to any movement of the contacts as isdisclosed and broadly claimed in the copending applicatiomSerial No.317,564, referred to above.

In order to release latch 43 from the restraining position indicated inFig. 4 when the circuit breaker I0 is open, I again use the sametripping means, namely, the slotted connection between 3| and crank 33for release of latch 43. The end 3| of link 3| is adapted to engage theprojecting tip 5| of the back plate 5| of latch 43.

With this arrangement, the initial movement to the right of piston 29when the circuit breaker is open by virtue of the lost-motion connectionbetween link 3| and crank 33 will cause the end 3| of link 3| to rotatelatch 43 in a counterclockwise direction to the position indicated inFig. 5, whereupon roller 41 is released so that subsequent closingmovement of circuit breaker l may be permitted.

In view of the detailed description included above, the operation or mydouble-latched restraining means will be obvious to thos skilled in theart. By means of a single latch 43, I have provided an arrangement inwhich an electric switch may be held in either its open or its closedposition without danger of movement or the relatively movable contactsdue to vibration or the like. Furthermore, th lost-motion connectionbetween link 3| and crank 33 eifects the unlocking of latch 43 fromeither 01' its two restraining positions.

It will be apparent to those skilled in the art that my invention is notlimited to the particular construction shown but that changes andmodifications may be made without departing from the spirit and scope ormy invention and I aim in the appended claims to cover all such changesand modifications.

What I claim as new and desire to secure by Letters Patent oi! theUnited States is:

1. In combination with an electric switch comprising a plurality ofrelatively movable contacts, means for producing relative movementbetween said contacts, a restraining means comprising a single movablemember constructed so as to hold said relatively movable contacts in aplurality of predetermined positions, and means operative upon operationof said first-named means for releasing said restraining means at eachof said predetermined positions of said relatively movable contacts.

2. In combination with an electric switch comprising a plurality ofrelatively movable contacts, means for producing relative movementbetween said contacts, a restraining means comprising a single movablemember constructed so as to hold said relatively movable contacts ineither the fully open or the fully closed position, and means operativeupon operation of said first-named means for releasing said restrainingmeans at either the fully open or the fully closed position 01' saidelectric switch.

3. In combination with an electric switch comprising a pair ofrelatively movable contacts, means for producing relative movementbetween said contacts, a single restraining means constructed so as tohold said relatively movable contacts in either the fully open or thefully closed position 01 said electric switch, and a lostmotionconnection interposed between said firstmentioned means and one of saidrelatively movable contacts for releasing said restraining means at boththe fully open and fully closed position oi said electric switch.

4. In combination with an electric switch comprising a pair ofrelatively movable contacts, motive means for producing relativemovement between said contacts, a single pivotally mounted restraininglatch constructed so as to lock said electric switch open againstclosing movement due to vibration or the like when in one position andto hold said electric switch closed when in another position, and meansincluding a lostmotion connection interposed between said motive meansand one of said relatively movable contacts for releasing saidrestraining latch from either of its locking positions upon initialoperation of said motive means.

5. In combination with an electric switch comprising a pair ofrelatively movable contacts, motive means for producing relativemovement between said contacts, a single pivotally mounted restraininglatch constructed so as to lock said electric switch open againstclosing movement due to vibration or the like when in one position andto hold said electric switch closed when in another position, and meansincluding a lost-motion connection comprising a pin and slot arrangementinterposed between said motive means and one of said relatively movablecontacts for releasing said restraining latch from either of its lockingpositions upon initial operation of said motive means.

6. In combination with an electric switch comprising a pair ofrelatively movable contacts, a fluid motor for producing relativemovement between said contacts, an operating mechanism for interrelatingsaid fluid motor and one of said relatively movable contacts, apivotally mounted latch including a pair of cam faces constructed sothat one or said cam faces engages with said operating mechanism to locksaid electric switch against closing movement due to vibration or thelike when in the substantially fully open position and the other of saidcam faces engages with said Operating mechanism to lock said electricswitch against opening movement when in the substantially fully closedposition, and means including a lost-motion connection interposedbetween said fluid motor and one of said relatively movable contacts forcausing disengagement of each of said cam faces from said operatingmechanism in either of the locking positions of said latch upon initialoperation or said motive means to permit subsequent relative movement ofsaid contacts.

' JOHN D. GAYER.

